HMS Avenger was built in the USA at Sun Shipbuilding, Chester, Pennsylvania, and laid down as mercantile Rio Hudson, where she was launched 27 November 1940 and subsequently converted as BAVG-2. She was transferred to the RN and commissioned 2 March 1942.

Following sea trials, she left New York in a tanker convoy and arrived on the Clyde in May 1942 where further modifications took place.

On 3 September 1942 HMS Avenger left Scapa Flow on her first official active duty, as an escort to convoy PQ18 to the north of Russia. She was equipped with 12 Sea Hurricanes and 3 Swordfish aircraft. Her aircraft sank the German submarine U-589 on 14 September 1942 with the assistance of the destroyer HMS Onslow.

She arrived back in Scapa Flow on 3 October 1942. Her Swordfish had flown 32 sorties and attacked 6 of the 16 U-Boats sighted, while the Hurricanes had destroyed and damaged 26 aircraft in 31 combats during 59 sorties. They had engaged German U-Boats, flying boats, Junkers Ju88 bombers and Heinkel He111 bombers. In all 13 merchant ships were lost, but the convoy claimed 42 German aircraft destroyed.

In her second operation, Avenger was ordered to take part in Operation "Torch", the invasion of North Africa. She left the Clyde on 22 October 1942 with her sister-ship HMS Biter and the Fleet Carrier HMS Victorious, to join the slow assault convoy KMS1. On 7 November 1942, HMS Avenger left the convoy and sailed to join HMS Argus off Algiers. From here, the combined ships' 30 Sea Hurricanes and Seafires would provide fighter cover for landings planned for dawn on 8 November 1942. No airborne opposition was encountered on 8 or 9 November and the Vichy French in Algiers surrendered earlier than expected. The Royal Air Force assumed responsibility for air defence, and with her aircraft ashore, Avenger was excused from duties. On 10 November she entered Algiers harbour to undertake repairs to problems with her engines, which had reduced her maximum speed to only 14 knots.

After taking part in Operation Torch landings of North Africa in November 1942, she departed Gibraltar with convoy MKF 1 on 14 November, heading home to the Clyde in the UK. At 0305 on 15 November, Avenger was torpedoed by U-155. Avenger (Cdr. Anthony Paul Colthurst, DSO, RN) was hit on the port side amidships, which in turn ignited her bomb room, blowing out the centre section of the ship. Her bow and stern sections rose in the air and sunk within 2 minutes in position 36º15'N, 07º45'W, leaving only 12 survivors.